Packing box



FIG. 1 is a front elevational view of a packing box showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a right side elevational view thereof, the left side being the same in appearance as the right side;

FIG. 4 is a top plan view thereof, the bottom being the same in appearance as the top; and,

FIG. 5 is a top and right front perspective view thereof. 

The ornamental design for a packing box, as shown and described. 